CN109429502B

CN109429502B - Turbocharging system

Info

Publication number: CN109429502B
Application number: CN201780040812.0A
Authority: CN
Inventors: J·P·麦克亨利; G·C·詹克斯; R·M·华莱士
Original assignee: BorgWarner Inc
Current assignee: BorgWarner Inc
Priority date: 2016-06-30
Filing date: 2017-06-28
Publication date: 2020-12-11
Anticipated expiration: 2037-06-28
Also published as: WO2018005605A1; EP3478950A1; EP3478950B1; US10947931B2; CN109429502A; US20190107082A1; JP2019519720A; US10100785B2; KR20190023078A; US20180003133A1

Abstract

The invention provides a turbocharging system. The turbocharger system may include a bearing housing in which the shaft may be supported for rotation by bearings. The compressor wheel may be disposed on the shaft. The compressor cover may be coupled with the bearing housing such that a compressor body may be formed and a chamber in which the compressor impeller may rotate may be defined. The diffuser may extend radially outward from the chamber and may receive gas from the compressor wheel. The compressor body may have an inlet that may receive a quantity of exhaust gas. The EGR distribution chamber may be defined within the compressor body and may extend around the shaft. The EGR inlet passage may extend from the inlet to the EGR distribution chamber into the bearing housing. The EGR passage may extend from the EGR distribution chamber to the diffuser.

Description

Turbocharging system

Cross Reference to Related Applications

This application claims the benefit of U.S. application serial No. 15/197,921 filed on 30/6/2016.

Technical Field

The field to which the disclosure generally relates includes turbocharging systems for internal combustion engines, and more particularly, exhaust gas driven turbocharging systems.

Background

The engine air intake system may generally include a charging system in which exhaust gas produced by combustion of fuel is passed through a turbine that drives a compressor. The engine intake air may be mixed with the recirculated exhaust gas, and the mixture may be directed to a compressor that charges an intake system of the engine.

Disclosure of Invention

Many exemplary variations may relate to a product that may include a bearing housing in which a shaft may be supported for rotation by bearings. The compressor wheel may be disposed on the shaft. The compressor cover may be coupled with the bearing housing such that a compressor body may be formed and a chamber in which the compressor impeller may rotate may be defined. The diffuser may extend radially outward from the chamber and may receive gas from the compressor wheel. The compressor body may have an inlet that may receive a quantity of exhaust gas. The EGR distribution chamber may be defined within the compressor body and may extend around the shaft. The EGR inlet passage may extend from the inlet to the EGR distribution chamber into the bearing housing. The EGR passage may extend from the EGR distribution chamber to the diffuser.

Other exemplary variations within the scope of the invention will become apparent from the detailed description provided herein. It should be understood that the detailed description and specific examples, while disclosing variations within the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Drawings

Selected examples of variations within the scope of the present invention will be more fully understood from the detailed description and the accompanying drawings, wherein:

fig. 1 is a schematic diagram of an engine breathing system according to a number of variations.

Fig. 2 is a cross-sectional view of a product according to a number of variations.

Fig. 3 is a perspective cut-away view of a product according to a number of variations, with the compressor cover removed.

Fig. 4 is a cross-sectional view of a product according to a number of variations.

Fig. 5 is a cross-sectional view of a product according to a number of variations.

Fig. 6 is a cross-sectional view of a product according to a number of variations.

Detailed Description

The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the invention, its application, or uses.

In a number of exemplary variations as shown in FIG. 1, the engine breathing system 12 may include an internal combustion engine 14, and the internal combustion engine 14 may have a plurality of cylinders for controlled combustion of fuel to generate power. Exhaust gas resulting from combustion may exit the engine 14 at an exhaust manifold 16, and the exhaust manifold 16 may be connected to an exhaust passage 18. Exhaust passage 18 may lead to a turbine 20. The exhaust gas may expand in the turbine 20, releasing energy to rotate the turbine wheel 22. Exhaust gas may continue from the turbine 20 through the exhaust passage 24 to the exhaust outlet 26.

In many variations, the turbine wheel 22 may be connected to the compressor wheel 28, such as by a shaft 30. The compressor wheel 28 may be disposed within a compressor 32. By the act of directing exhaust gas to the turbine wheel 22, the compressor wheel 28 may be rotated by a shaft 30. The rotating compressor wheel 28 may intake air through an intake passage 34 and compress it, thereby charging an intake system 36 of the engine 14 through a passage 38, a charge air cooler 40, a passage 42, and an intake manifold 44. An intake throttle valve 45 may be provided to selectively throttle the passage 42 when desired, and in many variations the intake throttle valve 45 may be omitted.

In many variations, the compressor 32 may draw in exhaust gas through an Exhaust Gas Recirculation (EGR) circuit. The EGR circuit may include an EGR passage 46, which may lead to a heat exchanger 48, and may extend through a valve 50 for regulating exhaust gas flow through the EGR circuit. The EGR path 46 may pass through a heat exchanger 48 and a valve 50, and may then lead directly to the compressor 32 at an inlet 52. The EGR passage 46 may be connected to the exhaust system at any of a number of locations, including but not limited to the exhaust passage 18 or the exhaust manifold 16. When connected upstream of turbine 20, the turbine size may be selected to provide a desired pressure for feeding EGR passage 46. A valved wastegate duct (not shown) may provide a bypass around the turbine wheel 22. Exhaust gas exiting the system may pass through an aftertreatment device 54 and an exhaust throttle 56. The exhaust throttle valve 56 may be selectively throttled as needed to increase the flow of exhaust gas through the EGR loop. In many variations, the pressure generated by sizing the turbine 20 to feed the EGR passage 46 may allow the exhaust throttle to be omitted.

The formation of undesirable compounds during combustion in the internal combustion engine 14 can be reduced by exhaust gas recirculation. A pressure differential is required to drive the flow of exhaust gas from the exhaust passage 24 to the intake system. Such pressure requirements may result in lower efficiency and higher brake specific fuel consumption, for example, if the exhaust throttle 56 is cycled closed to throttle the exhaust flow. For example, when the pressure differential between intake manifold 44 and exhaust manifold 16 is high, the engine is required to do more work. In many variations, flow fields within the compressor 32 stages may be used to reduce the required pressure in the exhaust manifold 16 and exhaust passage 18, and thus increase overall powertrain efficiency. This is because there is less pressure increase from intake manifold 44 to exhaust manifold 16. This may be accomplished by injecting an EGR flow, wherein the intake system has a low static pressure, thereby reducing the static pressure requirement for supply from the exhaust system to EGR passage 46. At the system level, the reduction in exhaust pressure may make the pressure increase on the cylinder head of the engine 14 more favorable, thereby reducing emissions and achieving better fuel economy. Although the pressure at the inlet of the compressor wheel 28 may be lowest, it has been found that injecting the exhaust gas in this region requires additional work by the compressor 32 to recompress the gas. It has also been found that the lowest pressure region after the inlet is located at the compressor wheel outlet where the flow rate is highest. The difference between the static pressure at the outlet of the compressor wheel 28 and the discharge pressure at the inlet 52 may exceed 150kPa, as measured on a gas cabinet, depending on the rotational speed. By supplying EGR to the high speed region of the compressor 32, the pressure differential used to drive the EGR is significantly increased, thus reducing or eliminating the need for throttling (cycling at least partially closed), the need for an exhaust throttle valve 56, and/or enabling the use of a higher flow turbine 20.

Referring to fig. 2 and 3, the EGR path in the product is shown in more detail. The description may include a reference to an axial direction, indicated by reference numeral 61, meaning a direction along the axis of the shaft 30 (as indicated by reference numeral 61), or a direction parallel thereto. The description may include reference to a radial direction, indicated by reference numeral 63, meaning a direction toward or away from the axis of the shaft 30 at any angle within a 360 degree range about the shaft 30. The shaft 30 may be supported in a bearing housing 60, and the bearing housing 60 may be disposed between the compressor 32 and the turbine 20. The shaft 30 may be supported by bearings 31. The compressor wheel 28 may be disposed in a chamber 62, which chamber 62 may be defined by a bearing housing 60 and a compressor cover 64. An inlet 68 of the chamber 62 may be defined by the compressor cover 64 through which air may be drawn by the compressor wheel 28. Air may be delivered from the compressor wheel 28 through a diffuser 70 and may be collected in a volute 72 for communication with the passage 38. The diffuser 70 may be defined between the bearing housing 60 and the compressor cover 64 at a diffuser face 74. The diffuser 70 may form an annular passage extending radially outward from the chamber 62 at the compressor wheel tip 76 to the volute 72. Air drawn in through the inlet 68 may be acted upon by the compressor wheel 28 in the chamber 62 and delivered through the diffuser 70 to the volute 72. The airflow exiting the compressor wheel tip 76 enters an adjacent portion of the diffuser 70, which may be referred to as a fresh air port 78. The fresh air port 78 is the portion of the diffuser 70 closest to the compressor wheel 28 that has the highest gas flow rate because the cross-sectional area of the diffuser 70 becomes smaller radially inward and larger radially outward.

In many variations, the EGR inlet 52 may be connected with an EGR inlet passage 80, the EGR inlet passage 80 extending radially inward into the bearing housing 60 to an EGR distribution chamber 82. EGR inlet passage 80 may extend toward axis 61 of shaft 30 and may be disposed at an angle relative to shaft 30. EGR inlet passage 80 may be directed directly toward axis 61. The EGR inlet passage 80 may be a single bore that may include the only opening to the EGR distribution chamber 82 for providing EGR. EGR inlet passage 80, including at EGR inlet 52, may be angled with respect to axis 61 rather than perpendicular to axis 61. As such, the angle of EGR inlet passage 80 with respect to axis 61 may be oblique. This makes formation easier, including in existing compressor designs, where the available space for EGR inlet passage 80 may be utilized. The EGR distribution chamber 82 may be defined entirely within the bearing housing 60 and may extend to surround the shaft 30. The EGR distribution chamber 82 may be of uniform size over its circumferential length about the shaft 30. In other words, the opening cross section of the EGR distribution chamber 82 may have a uniform cross-sectional opening area at all points around its periphery. For greater structural simplicity, the cross-section may be rectangular and the entire EGR distribution chamber 82 may have an annular shape, both of which contribute to easier chamber formation. EGR passage 84 may connect EGR distribution cavity 82 with fresh air port 78 and may be open at opening 79 by diffuser face 74. The opening 79 may be spaced from the compressor wheel tip 76 such that an annular chamfer 86 may be defined by the bearing housing 60 about the compressor wheel tip 76. The EGR passage 84 may be angled radially outward such that EGR gas flowing therethrough is directed radially outward, similar to air flowing through the fresh air port 78. The low pressure at the high velocity section of the diffuser 70 advantageously reduces the pressure level required at the exhaust passage 24 to supply EGR gas to the intake manifold 44. An annular chamfer 86 may be defined on the protrusion 81 of the bearing housing 60, the protrusion 81 may include an axially extending wall 83 adjacent the diffuser face 74, the axially extending wall 83 extending to a location disposed directly radially outward of a portion of the compressor wheel tip 76, and the axially extending wall 83 defining a radially inner end of the diffuser face 74. A portion 85 of diffuser face 74 extends radially outward from the edge of axially extending wall 83 to opening 79. An annular ramp 86 extends rearwardly from the radially outermost edge of portion 85 at an angle towards axis 30 such that projection 81 forms the shape of a foot with toes 87 pointing in a radially outward direction away from axis 30. In many variations, the EGR distribution cavity 82 may be formed in a separate backing plate component that may define the diffuser face 74, may be connected to the remainder of the bearing housing 60, and may form a portion of the bearing housing 60. Thus, reference to the bearing housing 60 may include a bearing housing 60 having a separate backing plate. The compressor 32 may include a compressor body 61, which may include a compressor cover 64 and a bearing housing 60 and/or separate backing plates thereof.

In various modifications as shown in fig. 4, a portion of the bearing housing 60 where the annular slope 86 (the protrusion 81) is formed may be omitted. The EGR inlet passage 80 may extend through the bearing housing 60 to an EGR distribution chamber 82. The EGR distribution cavity 82 may be connected with an EGR passage 88, the EGR passage 88 including an opening 90 to the fresh air port 78 and a back side 92 of the compressor wheel 28, the back side 92 being adjacent the compressor wheel tip 76. A radially innermost wall 89 on the bearing housing 60 defining the EGR distribution chamber 82 may extend axially and may be directed toward an aft side 92 of the compressor wheel 28, which is radially inward of the compressor wheel tip 76.

In a number of variations as shown in fig. 5, the EGR inlet passage 80 may extend through the bearing housing 60 to the EGR distribution chamber 82. EGR distribution cavity 82 may be radially inward and may connect with an EGR passage 94, EGR passage 94 including an opening 96 to a pocket 98 on a back face 92 of compressor wheel 28. The pocket 98 may be defined as an area bounded on its axial side by the compressor wheel 28 and the bearing housing 60, an area bounded on its radial side by the compressor wheel tip 76 and the shaft 30, or a ring 97 that may rotate with the shaft 30. The EGR passage 94 may extend radially inward from the EGR distribution cavity 82 and may be disposed toward the compressor-side bearing housing seal assembly 99. The introduction of EGR gas at this point may increase the pressure in compressor wheel pocket 98, helping to equalize the pressure across seal assembly 99. This helps to retain the lubricant within the bearing housing 60. After flowing into the pocket 98, the EGR flow is then entrained with air at the outlet of the compressor wheel 28 through the fresh air port 78.

In a plurality of variations as shown in fig. 6, the EGR distribution chamber 101 may be formed in the compressor cover 64. The EGR distribution chamber 101 may be formed entirely within the compressor cover 64 and may have a rectangular cross-section with a consistent open cross-sectional area around the shaft 30, forming an annulus. EGR distribution chamber 101 may be disposed completely radially inward relative to volute 72. An EGR passage 102 may connect the EGR distribution chamber 101 with the fresh air port 78 and may open to the diffuser 70 at an opening 104 to the fresh air port 78. An EGR inlet passage (not shown) may extend into the compressor cover 64 up to the EGR distribution chamber 101 for supplying EGR gas thereto.

With the variations described herein, the pressure of exhaust manifold 16 may be reduced while keeping the pressure of intake manifold 44 constant, and a more favorable pressure differential may be created across the cylinder head of engine 14. As a result, the engine 14 may require less work to move the air, or the engine 14 may do more work during the gas exchange process. Pumping provides an efficiency advantage over engine Brake Mean Effective Pressure (BMEP) in terms of mean effective pressure (MEP pumping).

The following description of variations is merely illustrative of components, elements, acts, products and methods which are considered to be within the scope of the present invention and is not intended to limit the scope in any way by what is specifically disclosed or not explicitly set forth. The components, elements, acts, products and methods may be combined and rearranged other than as specifically described herein while remaining within the scope of the present invention.

Variant 1 may relate to a product and may comprise a bearing housing in which the shaft may be supported for rotation by bearings. The compressor wheel may be disposed on the shaft. The compressor cover may be connected with the bearing housing and may form a compressor body that may define a chamber in which the compressor impeller may rotate. The diffuser may extend radially outward from the chamber and may receive gas from the compressor wheel. The compressor body may have an inlet that may receive a quantity of exhaust gas. The EGR distribution chamber may be defined within the compressor body and may extend around the shaft. The EGR inlet passage may extend from the inlet to the EGR distribution chamber into the bearing housing. The EGR passage may extend from the EGR distribution chamber to the diffuser.

Variation 2 may include a product according to variation 1, wherein the shaft may rotate on an axis, and the EGR inlet passage may extend in a direction toward the axis.

Variation 3 may include a product according to variation 1 wherein the EGR distribution chamber may extend circumferentially around the shaft and may have a uniform cross-section at any point in the circumferential direction.

Variation 4 may include a product according to variation 1 wherein the compressor wheel may include a compressor wheel tip at a radially outermost periphery thereof. The bearing housing may include a diffuser surface that may define a side of the diffuser extending radially toward the shaft and may be directed toward the compressor wheel tip.

Variation 5 may include a product according to variation 1 wherein the compressor wheel and the bearing housing may define a pocket therebetween, which may extend radially inward from a radially outermost end of the compressor wheel. The EGR path may lead directly into the pocket.

Variation 6 may include a product according to variation 1, wherein the shaft may rotate on an axis, and the EGR inlet passage may extend to point toward the axis, which may be an oblique angle.

Variation 7 may include a product according to variation 1 and may include an engine, an exhaust passage to carry exhaust gas away from the engine, and an EGR passage to connect the exhaust passage with an EGR inlet passage.

Variation 8 may include a method of operating the product of variation 7, and may include providing an exhaust throttle valve in the exhaust passage. Exhaust gas may be delivered to the EGR inlet passage without throttling the exhaust throttle valve.

Variation 9 may include the method according to variation 8 and may include providing a pocket between the compressor wheel and the bearing housing, the pocket may extend inwardly in a radial direction from a radially outermost end of the compressor wheel. At least a portion of the EGR passage may be directed to supply exhaust gas directly into the pocket.

Variant 10 may relate to a product that may include a bearing housing in which a shaft may be supported for rotation by bearings. The compressor wheel may be disposed on the shaft. The compressor cover may be connected with the bearing housing and may form a compressor body that may define a chamber in which the compressor wheel may rotate, the chamber defining an air inlet through which air may be directed to the chamber. The diffuser may extend radially outward from the chamber and may receive gas from the compressor wheel. An EGR inlet on the compressor body may receive a quantity of exhaust gas. The EGR distribution chamber may be defined within the compressor body and may extend around the shaft. The EGR inlet passage may extend from the EGR inlet to the EGR distribution chamber into the compressor body. The EGR passage may extend from the EGR distribution chamber to the diffuser.

Variation 11 may include a product according to variation 10 wherein the EGR distribution chamber may extend circumferentially around the shaft and may have a uniform cross-section at any point in the circumferential direction.

Variation 12 may include a product according to variation 10 wherein the compressor wheel may include a compressor wheel tip at its radially outermost periphery. The bearing housing may include a diffuser surface defining a side of the diffuser extending radially toward the shaft and may be directed toward the compressor wheel tip.

Variation 13 may include a product according to variation 10 wherein the compressor wheel and bearing housing may define a pocket therebetween, which may extend radially inward from a radially outermost end of the compressor wheel. The EGR path may lead directly into the pocket.

Variation 14 may include a product according to variation 10 wherein the shaft may rotate on an axis and the EGR inlet passage may be directed toward the axis.

Variation 15 may include a product according to variation 10 wherein the EGR distribution chamber may be annular and may have a rectangular cross-section.

The above description of selected variations within the scope of the invention is merely illustrative in nature and, thus, variations or modifications thereof are not to be regarded as a departure from the spirit and scope of the invention.

Claims

1. A turbocharger system comprising a bearing housing in which a shaft is supported for rotation by bearings; a compressor wheel disposed on the shaft; a compressor cover connected with the bearing housing to form a compressor body defining a chamber in which the compressor impeller rotates; a diffuser extending radially outwardly from the chamber and receiving gas from the compressor wheel; an inlet on the compressor body to receive a quantity of exhaust gas; an EGR distribution chamber defined entirely within the compressor body and extending about the shaft; an EGR inlet passage extending from the inlet to the EGR distribution chamber up to the bearing housing; and an EGR passage extending from the EGR distribution chamber to the diffuser,

wherein the compressor wheel and bearing housing define a pocket therebetween extending radially inward from a radially outermost end of the compressor wheel, the EGR passage opening directly into the pocket.

2. The turbocharging system of claim 1, wherein said shaft rotates about an axis and said EGR inlet passage extends in a direction toward said axis.

3. The turbocharging system of claim 1, wherein said EGR distribution chamber extends circumferentially about said shaft and has a uniform cross-section at any point in the circumferential direction.

4. The turbocharging system of claim 1, wherein said compressor wheel includes a compressor wheel tip at a radially outermost periphery thereof, and wherein said bearing housing includes a diffuser face defining a side of said diffuser extending radially toward said shaft and directed toward said compressor wheel tip.

5. The turbocharging system of claim 1, wherein said shaft rotates about an axis and said EGR inlet passage extends at an oblique angle toward said axis.

6. The turbocharging system of claim 1, including an engine, an exhaust passage carrying exhaust gases away from said engine, and an EGR passage connecting said exhaust passage with said EGR inlet passage.

7. A method of operating the turbocharging system of claim 6, comprising providing an exhaust throttle valve in said exhaust passage and delivering exhaust gas to said EGR inlet passage without throttling said exhaust throttle valve.

8. The method of claim 7, comprising providing a pocket between the compressor wheel and the bearing housing, the pocket extending radially inward from a radially outermost end of the compressor wheel, and directing at least a portion of the EGR passage to supply exhaust gas directly into the pocket.

9. A turbocharger system comprising a bearing housing in which a shaft is supported for rotation by bearings; a compressor wheel disposed on the shaft; a compressor cover connected with the bearing housing to form a compressor body defining a chamber in which the compressor wheel rotates, the chamber defining an air inlet through which air may be directed to the chamber; a diffuser extending radially outwardly from the chamber and receiving gas from the compressor wheel; an EGR inlet port on the compressor body receiving a quantity of exhaust gas; an EGR distribution chamber defined within the compressor body and extending about the shaft; an EGR inlet passage extending from the EGR inlet to the EGR distribution chamber up to the compressor body; and an EGR passage extending from the EGR distribution chamber to the diffuser,

10. The turbocharging system of claim 9, wherein said EGR distribution chamber extends circumferentially about said shaft and has a uniform cross-section at any point in the circumferential direction.

11. The turbocharging system of claim 9, wherein said compressor wheel includes a compressor wheel tip at a radially outermost periphery thereof, and wherein said bearing housing includes a diffuser surface defining a side of said diffuser extending radially toward said shaft and directed toward said compressor wheel tip.

12. The turbocharging system of claim 9, wherein said shaft rotates about an axis and said EGR inlet passage is directed toward said axis.

13. The turbocharging system of claim 9, wherein said EGR distribution chamber is annular and has a rectangular cross-section.